Mechanism



(No Mobiel.) 2 Sheets-Sheet 1. T. A. WESTON. HOISTING M-BGHANISM. N0. 320,317. Patented June 16, 1885.

a f A Y V A (No Model.)

, 2 Sheets-Sheet 2. T. A. WESTON. HOISTING MEGHANISM.

Patented June 16,. 1885.

o INVENTGR Thomas Weson, By his .ltorneys 6M. @y

f FFICI.,

THOMAS A. VESTON, OF STAMFORD, CONNECTICUT, ASSIGNOR TO THE YALE & TOVNE MANUFACTURING COMPANY, OF SAME PLACE.

HOISTING VIECHANISIVI.

SUJCIFICATEON forming part of Letters Patent No. 320,317, dated June 16, 1885.

Application filed -Ianuary 8, ISB-l.' (No model.)

To @ZZ whom t may concern,.-

Be it known that 1, THoMAs A. W EsToN, of Stamford, in the county of Fairlield and State of Connecticut, have invented an Improved Hoisting Apparatus, of which the following is a specification, reference being had to the accoinpanying drawings.

The object of my invention is to obtain a very compact and portable hoisting machine, the mechanical purchase or power of which consists, mainly, in the plain spurgearing I employ, in order that the machine may have little friction, and which machine shall be always selfehccked against backward motion or turning` down of the load during both operations of hoisting and lowering.

The safety-lowering and self-sustaining feature employed I do not claim, broadly, as it forms the subject of my Letters Patent of the United States, No. 98,000, December 14, 1869, and in the particular application to a pulleyblock or portable hoist is shown in Fig. 20 of my English Letters Patent, No. 900, March 15, 1873.

In the drawings the chains and lower block are not shown, being of the ordinary kind.

Figure I is an elevation with the plain spurgearing exposed. Eig. 2 is a longitudinal transverse section through theline 2 2, Fig. 1. Fig. 8 is an elevation on the sprocket-wl'icel side ofthe block. Fig. 4 is a Vertical transverse section. Fig. 5 is a sectional view of a ratchet-pawl and segment of t-he ratchet-wheel in the line 5, Fig. 8. Fig. 6 is a sectional view of a piece forming a brace or stay to the frame sides, and also a shaft bearing chainguides and chain stripper or clearer.

A is the main shaft, carried in bearings B, projecting inwardly toward each other from the inner sides of the main frame B. The main hoisting-sheave or chain wheel C and spurwheel D are respectively keyed upon or rmly xed to the shaft A. The pinion E', fixed to or forming part of the shaft E, engages by its teeth with the wheel D. The shaft E at its other end carries upon a screw-thread the drivingsprocket-wheel H, correspondingly threaded in its boss to travel on the shaft. The shaft E also carries at the same end, but firmly se cured by the key and screw-nut 0, the abutment collar and disk-hub E. The latter has a disk-carrying hub F of smooth periphery for the ratchet-wheel G, and its disks to turn upon. It has also in its peripherysunken key-grooves or slots, El, to receive projections on the central aperture of the intermediate disks E, and thus to hold them securely, but permitting their longitudinal motion on the shaft.

G is a ratchet-wheel rim formed upon the middle friction-disk, G. The inner annular surface of the said rim, forming a recess or shallow cylinder on each side of the llange or disk G,l'1as thereon lugs Gengaging securely the friction-disks G, but permitting their longitudinal movement to or from the adjacent disks. The said disks G Gii are bored centrally to turn upon the diskhub E, which supports them. The intermediate disks,F3,of the hub are at their periphery free and clear of contact with the inner su rface of the ratchetrim G, so that the one set of disks E may, in lowering aload or in the backward driving of the shaft E, have an independent rotary frictional brake action upon the then stationary disks G G, which are held at rest by the lugs G2 and the pawls I. The said two sets ofdisks are intended when lowering a load to furnish a large area for frietional brake-action between the backward-1noving parts, viz., the sprocket-wheel H and hub E, and thc then stationary parts, the ratchet-wheel or rim G and the disks G G,

The said disk-brake is made in accordance with the specification of my United States Patent No. 75,227, March 8, 1808.

My present improvement in the said diskbrake consists, chiefly, in making the ratchetwheel of an annular or hoop forni, supported by the disks it encircles and engages with by their slotted peripheries, the said disks turning upon the central hub, which also carries the intermediate disks engaged therewith by slots and keys or projections. The said annular ratchet-wheel is by preference cast or formed in one piece witha flange ordisk forniing one of the acting friction-disks of the series belonging to and engaging with the ratchet-wheel. I am thus enabled to bring the ratchet-wheel and disk-brake into the space or thickness of a plain ratchet-wheel occupying no more space lengthwise upon the I am further enabled by my invention shaft.

IOO

to make the said ratchet wheel, the diskbrake, the safety-incline device, and also the driving-pulley or sprocket-wheel occupy, all together upon the shaft, only the space needed for a commonv sprocket-wheel. The said driving-pulley or sprocket-wheel, safety-incline device, frictional-disk ratchet-wheel, and differential pawls constitute myimproved safety sprocket-wheel, which contains within its own thickness substantially all the foregoing parts, yielding a brake-action self -ehecked at all times in hoisting or in lowering by its continuous safety lowering motion.

The ratchet-teeth of the rim G are spaced apart,so as to act differentially or alternately with the pawls I I, which-latter are pivoted to the outer frame, B". The said pawls are recessed around their pivot-hole to receive and inclose from dirt or injury or displacement the curved springs l, the curved form securing the springs from breakage by their ordinary bending action. Such pawls and self-contained springs are therefore well adapted for use upon the frames of hoists,and particularly of pulleyblocks which are exposed to rough usage as they are dragged about from place to place.

For like reasons the spur-gearing is coveredr by a casing or box, B2, which adds stiffness to the frame, as does also the cross-stay piece K, (shown separately in Fig. 6,) which piece also provides an ample bearing for the shaft E, chain-guides K K2, and a stripper or clearer, K, to secure the disengagement of the chain from the sheave as it passes away from the-latter.

An ordinary endless hand-chain is placed upon the sprocket-wheel H, and a strong lifting-chain( not endless) is placed on the sheave C, one end being secured to the eye B5 in the lower edge of the frame side, and from thence the chain descends to acommonsnatch-block. Passing beneath the sheave of the latter, and thus sustaining` it, the chain aseends through the chain-guide K to the hoisting side of the sheave C. Passing over the latter, and down through thecruciform guide-hole K2, the slack chain may hang downward freely; but for compaetness its loose end may be pinned to'any convenient pointin the lower part of the frame B. The frame B is provided with the ordinary cross-head B3 and hook B4.

The pinion E may, if desired, be engaged with an internally-toothed wheel in lieu of the plain one D, omitting the cover thereto.

The direction of motion in the several parts during hoisting is indicated by arrows, also by the direction of the pawls and ratchet-teeth, the latter never moving backward.

rlhe operation is as follows: rIhe sprocketwheel being driven in the direction for hoisting, it will at rst turn upon the shaft E, advancing along the screw-threads outward toward the collar F. It will then compress against the said collar F the intervening friction disks within the ratchet-rim G. The amount of compression is of course determined by the resistance of the load and varies therewith. The load thus insures for itself in excess always efiicient frietional adhesion between the disks and friction-surfaces of the sprocket-wheel and hub F, and those of the ratchet-wheel G to thus imite them alL rlhe pawls l arrest backward motion in the ratchet-wheel, so that at any instant the drivingforce may cease and the hand-chain be let go, when the load will remain safely suspended.

To lower the load, the sprocket-wheel H is turned backward. This motion unscrews it upon its threaded bearing on the shaft E, releasing from pressure the disks and collar F, and so soon as the pressure and resultant friction are thus sufficiently lessened, the load will descend and impel the ehain-sheave C, shaft A, spur-wheels, shaft E, collar or hub F, and its disks F3 backward, following closely the retiring motion of the sprocket-wheel H, and screwing the latter up again to compress the disks as fast as it is unscrewed from them by the continued backward pulling of the handehain. The load can therefore only be lowered by the continued backward driving of the sprocket-wheel, and,as when hoisting, the operator can instantly let go hishold uponthe hand-chain and leave the load safely suspended. Tere the disks all omitted except the one forming the fla-nge of the ratchet-rim, the hoist would be still operative and self-sustaining, but the wear of the singlefriction surfaces ot' the hub F and sprocket-wheel upon the intervened ratchet-Harige would be very rapid and the lowering motion not so smooth and even from the insufiicient brake area.

My improved frietional ratchet-wheel and brake occupies only the longitudinal space along the shaft necessary for its teeth to be of suftieient breadth, and the said ratchet-wheel and contents come substantially within the breadth or thickness of the sprocket-wheel rim, thus adding nothing to the bulk of this form of hoist, in which portability is the first essential, and in a less degree, only the compactness of my invention in this feature is as desirable for many fixed hoisting-machines.

By my invention I am also enabled to place the frame sides of the hoist very close together, leaving between them merely the space needed to accommodate the thickness of the main sheave C, from which the load hangs centrally in line with the suspending-hook B, y construction, nevertheless, affords ample length of bearing ,to both shafts A and E, and the external box of gearing on one side of the frame approximately balances the sprocketwheel on the other side and its self-contained fri ctional brake apparatus.

For the purpose of pulley-block construction there is an obvious advantage in the construction of my invention, consisting in placing the ratchet-wheel and collarF on the outer side of the said sprocket-wheel farthest from the hoist, for it permits the sprocket-wheel to have its plain side in close proximity to the hoist-frame, allowing only the very small clearance required for the sprocket-wheel to turn IOO IIO

free of contact with the frame and to traverse slightly upon its sere\\'-threaded shaft. Thus I avoid making the sprocket-wheel and shaft unduly overhung` or projected vfrom the hoisti'rame. In many forms of hoists it may simplify the frame to place the ratchet-wheeland collar on the side of the sprocket-wheel next the frame, when the pawls can be hung' to the main frame.

A helical incline orscrew-surface of one convolution upon the shalt E, in lieu of the continuous screw-th read and a correspondingl incline upon the boss of the sprocket-wheel, would effect the purposes of my invention; but not equally with the screw-thread, inasmuch as the latter affords a positiveretiring motion from the disks when it is turned backward 0n the shaft, and so more surely releases them from pressure when it is desired to lower the load or the unloaded chain and lower block.

\Vhen the main sheave is wholly unloaded, it can be driven backward by the sprocketwheel or driving-pulley H with apositive motion when the sprocket-wheel has been turned backward as far as it will go toward the inner end ofthe screw-thread. When desired, the said improved driving-pulley may be operated by a common crank-handle by spur-teeth in its outer periphery, or by a driving-band of any kind to which its periphery may have been adapted.

Having` thus described my invention7 what I claim. and desire to secure by Letters Patent of the United States, is-

l. A set of friction-disks loosely supported by a central hub and connected by a rim at their peripheries, substantially as described.

2. The combination of a sprocket-wheel, an

abutment-collar, and a screw-threaded shaft with which they both engage, so that the rotation of the wheel in one direction causes frictional contact, substantially as set forth.

3. A driving-pulley or sprocket-wheel provided with an internally screwed boss, a screwed shaft, friction-disks, ratchet-rim, or equivalent checking device, supporting-hub, and abutment collar, substantially as described.

4. A pulley-block frame provided with internal bearings for both the driving and main shafts, so that the width of the frame is not increased by said bearings.

5. In combination with a pulley-block frame, a stay or brace which serves as a shaft-bearing and also a chain-guide, substantially as described.

G. In a pulley-block, the combination of a main shaft and chain-sheave turning` upon inwardly-projeeting bearings which projeetinto recesses in the chain-sheave, substantially as described.

7. A pulley-block having combined with it differential ratchet and pawls, substantially as described.

8. In a hoist, the combination of a main frame, au abutment-collar, F, and a sprocketwheel interposed between the two, substantially as described.

In testimony whereof I have hereunto subscribed my name this 21st day of December, A. I). 18S-L.

THOS. A. TESTON \Vit,iicsses:

SonUYLna Mnnnrr'r, GEO. E. VHITE. 

